Scalable Syntheses of the Vaulted Biaryl Ligands VAPOL and VANOL via the Cycloaddition/Electrocyclization Cascade
作者:Zhensheng Ding、Wynter E. G. Osminski、Hong Ren、William D. Wulff
DOI:10.1021/op200088b
日期:2011.9.16
straightforward, inexpensive, efficient, and amenable to large-scale preparation of the ligands since minimum chromatographic purification is required. The key step in each synthesis is a cycloaddition/electrocyclic ring-opening/electrocyclic ring closure/tautomerization cascade that provides a direct one-step route to the monomers from which each ligand is prepared. Improved phenol coupling protocols